Generally, three virtual realities, i.e., an immersive virtual reality (VR), a desktop VR, and an augmented reality, have been widely used. The augmented reality is indicative of a user interface technique capable of correctly matching a virtual image generated by a computer with a real image viewed by a user. The above-mentioned augmented reality can provide a user with a higher reality and higher recognition accuracy.
In order to implement the above-mentioned augmented reality, a method for correctly estimating the movement of a camera or a target object is of importance. A method for implementing the above-mentioned augmented reality generally includes the following first and second methods.
The first method uses characteristics collected by objects existing in the real world, and is considered to be an ultimate purpose of the augmented reality field. However, if the number of characteristics collected by objects is a small number or an environment condition such as an illumination condition is unstable, performance is greatly deteriorated.
The second method uses known markers, and is more stable than the above-mentioned first method. In this case, it is indicative of an object artificially inserted in the real world to correctly estimate the movement of a camera or a target object, such that it may hide other objects or may be unpleasant to the eye. Due to the above-mentioned problems, the augmented reality technologies using the known marker have limited application.
The vision-based augmented reality system will hereinafter be described with reference to FIG. 1.
FIG. 1 is a conventional vision-based augmented reality system.
Referring to FIG. 1, the conventional vision-based augmented reality system includes a camera 11 for capturing a target object (TO) on which a visible marker (VM) is indicated; an image processor 12 for monitoring a position and attitude of the marker upon receiving a mark image indicated on the TO from the camera 11, tracking a position and pose of the TO, and rendering a virtual image to a TO image such that it generates a new image; and an output unit 13 for displaying the image received from the image processor 12 on a screen.
The above-mentioned augmented reality system uses the visible marker so that it correctly and rapidly implements the augmented reality. In this case, the marker is an artificial addition not present in the real world, such that the abovementioned augmented reality system has a disadvantage in that the marker hides a desired target object or is unpleasant to the eye. Also, the number of application fields of the abovementioned augmented reality system using the visible marker is very limited.
Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a vision-based augmented reality system using an invisible marker, which indicates an invisible marker on a target object to be tracked, and rapidly and correctly tracks the target object by detecting the invisible marker, such that it rapidly implements correct augmented reality, obviates problems generated when a visible marker is used, and is applicable to a variety of application fields.